We add a checkbox to out bulk update form to mark tickets as spam.
This box kept getting checked accidentally by our users even though
they claimed to not have touched it.
I finally figured it out. The “check all” button on the bulk update
form is too aggressive. Not only does it check all the tickets but it
also checks the “force change” checkbox, and any other checkbox that
might get added locally or to RT in the future. This bug exists in 3.6